Cities collect heat by absorbing the sun's energy on their black asphalt streets and between their tall buildings. Painting every roof over the next 20 years would offset all of the emissions from the world's cars, the study's authors said.

The soon to be published study gives some weight to the seemingly uncomplicated fix for a global problem, but will the release of the new study be enough to push for white roofs across the country? Head over to Treehugger for more figures from the study.Photo via Treehugger.